Pathogenicity and antibiotic susceptibility of <i style="">Vibrio</i> species isolated from moribund shrimps

Abstract

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> The population of <i style="">Vibrios</i> in diseased <i style="">Penaeus monodon</i> collected from culture ponds situated at Uran, Maharashtra (west coast of India) was studied. All animals collected were associated with more than one <i style="">Vibrio </i>species. Bacterial identification based on morphological and biochemical characteristics showed that four groups of Vibrios were present in shrimp hepatopancreas namely <i style="">Vibrio parahaemolyticus</i>, <i style="">V. alginolyticus</i>, <i style="">V. anguillarum </i>and <i style="">V. vulnificus</i>. The diseased shrimps displayed poor growth, lethargic movements, red discolouration and mortality. Experimental infection of healthy <i style="">P. monodon</i> using the isolated Vibrios produced varying degrees of mortality. Antibiotic resistance of the isolated Vibrios were investigated. All the four species were sensitive to Erythromycin, Chloramphenicol and Streptomycin. However, <i style="">V. parahaemolyticus</i> and <i style="">V. anguillarum</i> showed resistance to Oxytetracycline and Polymyxin-B respectively and <i style="">V. parahaemolyticus</i> and <i style="">V. vulnificus</i> were resistant to ampicillin. Hence, antibiotic application to control vibriosis in shrimp farms may have limited effectiveness, based on the efficacy of the drug, because of the development of resistant strains of bacteria.<b style=""></b> </smarttagtype></smarttagtype>